Item #15

Revise Cluster Subdivision regulations to provide appropriate incentives and to clarify requirements.

8.4 ALTERNATIVE DEVELOPMENT OPTION: CLUSTER HOUSING

8.4.1     Purpose

This section provides an optional process and standards for cluster housing development. The section is intended to encourage and allow for new concepts of traditional single-family housing development so that variations of design may be allowed, provided that the net residential density shall be no greater than permitted in the district in which the development is proposed. This shall not be construed as granting variances to relieve hardship.

A conventional subdivision generally covers the entire buildable portion of a site with residential lots. These lots are equal to or greater than a required minimum size designed to approximate the maximum permitted development density under the zoning regulations. A cluster subdivision allows for the reduction in the lot square footage minimum and setbacks provided that additional non-regulatory open space is provided. This permits greater net densities on portions of the site while permanently preserving additional open space and other important environment resources such as those identified in the Open Space and Historic Resources Plan.

This type of development is more sensitive to the natural environment by reducing the total amount of disturbance that may occur to the land in comparison to a conventional development while allowing the developer to reduce site improvement costs. The use of clustered subdivisions is not intended to allow increased density for undevelopable or unusable land already protected by other provisions of this Ordinance. The remnant land not designated as building lots is required to be left undeveloped, and must serve the purpose of effective buffering, passive recreation, and protection of significant vegetation, significant historic preservation or scenic qualities.

8.4.2     Applicability

The cluster development option is available for property located within a zoning district that permits single-family detached dwelling units (e.g., TR, R-8, R-12, R-20). However, the development of the property must still comply with all zoning conditions when using the cluster option. The size of the tract used under this option must be a minimum of ten (10) acres.

8.4.3     Approval of Cluster Site and/or Subdivision Plans

The approval authority, Staff or Town Council, may allow subdivision development on reduced lot sizes in return for the provision of additional open space and other design requirements set forth within this Section. In order to approve a development plan using this option, the Town must determine that the benefits of the cluster approach will prevent the loss of natural features without increasing the overall density or impervious surface of the development. Cluster developments follow the same review and approval process that conventional developments follow as required by this Ordinance.

8.4.4     Allowable Density, Lot Size and Open Space Requirements

An increase in the number of lots above the number of lots permitted by the underlying zoning (base number of lots) is allowed provided the development plan meets open space requirements and other design requirements set forth within the overlay. In no case shall the density of the development exceed the maximum permitted density of the site’s designated zoning district.

8.4.5     Calculating Base Number of Lots

The base number of lots is the permitted number of lots using development requirements of the underlying zoning district. The base number of lots is the starting point where additional lots may be permitted if additional non-regulatory open space is provided and other design requirements are met.

The applicant shall choose one (1) of the following methods for calculating the base number of lots:

(A)        The base number of lots may be determined by taking ninety (90) percent of the sum of the calculated buildable area and multiplying by the maximum density for the underlying zoning district. Reducing the total acreage by ten (10) percent accounts for the approximate area that would allocated to a roadway under a conventional subdivision. Buildable area within this Section is defined as the total land area excluding all floodplains, UTB/stream buffers, streetscape and other required buffers (see Chapter 7: Development and Design Standards).

Example: Site A

Total Acres: One hundred (100)

Acres in regulated/protected areas: Twenty (20)

Buildable area: One hundred (100) – Twenty (20) = Eighty (80)

Buildable area (Eighty (80) acres) x Ninety (90) percent = Seventy-two (72) acres

Seventy-two (72) acres x 3.63 dwelling units per acre (density permitted in R-12) = Two hundred sixty-one (261) base number of lots

(B)        The base number of lots may be determined based on a yield plan for the site, whereby the applicant presents a rough or sketch conventional subdivision development plan that fully complies with the development requirements of the underlying zoning for the site.

8.4.6     Maximum Density, Minimum Lot Size and Open Space Requirements

An increase in the number of lots (density bonus) is provided in exchange for the permanent preservation of additional open space and meeting other design requirements. An increase in the number of lots is achieved by allowing a lower minimum lot size (see Table 8.4-1 below).

Example:

8.4.7     Basic Requirements for Cluster Development

(A)        Cluster developments shall meet all requirements for a subdivision/site plan and all other applicable Town ordinances except for lot size, which is defined in this Section. Cluster subdivisions within the Jordan Lake watershed may be constructed without the standard curb and gutter required in other areas of Town. Alternative street designs may also be considered if such designs further protect on-site resources.

(B)        At a minimum, lot sizes and related setbacks shall conform to the standards of the TR District (see Chapter 6) for single-family detached or patio home development. If the zoning district allows for attached dwelling units, then lots smaller than 6,000 square feet shall be permitted. However, where lots in a cluster development abut a subdivision that is not developed as a cluster development or Planned Development, it shall have a side or rear yard not less than the required side or rear yard required on the abutting property.

(C)        Cluster subdivisions shall be adequately buffered from adjacent conventional subdivisions in accordance with Chapter 7 based on lot size.

(D)        Once the development is approved and platted, there shall be no further subdivision of land to obtain additional lots. However, easements for public utilities may be permitted.

8.4.8     Provision and Maintenance of Common Open Space and Facilities

All additional open space provided must meet the following standards:

(1)        Sixty (60) percent or more of all lots must abut open space (regulatory or non-regulatory). Abutting means being directly or across a road or street in either the front or rear of the lot for a distance measured along a lot line of no less than thirty (30) feet.

(2)        The open space shall be no less than thirty (30) feet in width at any point. Exceptions to the minimum width may be provided by the Planning Director if the narrower width provides a necessary pedestrian connection and a wider width is problematic due to topographic and/or shape constraints.

(3)        The open space shall be retained in a natural, undisturbed state, as practicable, with the exception of those activities permitted or for topographical constraints. If areas cannot be preserved in their natural state due to installation of infrastructure or is not vegetated, then a re-vegetation plan shall be provided.

(4)        Seventy-five (75) percent of the open space shall be in a contiguous tract only divided by roadways. Regulatory open space may be used to provide contiguity to the additional open space.

(5)        When applicable, additional open space shall connect with existing or future non-regulatory and/or regulatory open space lands on adjoining parcels and with public trails/greenways.

(6)        A minimum of twenty-five (25) percent of the total additional open space shall be maintained as central common area.

(a)        The central common area shall be a minimum of one hundred (100) feet in width and 20,000 square feet in size.

(b)        The central common area shall be located in a central position in the development and shall be surrounded by streets and/or building lots on at least three (3) sides. The intent is to avoid these areas being located only along the rear of lots.

(c)        Pedestrian access trails to the central common area shall be provided on four (4) sides unless topographic constraints make access impractical.

(d)        Active recreation facilities are not permitted in central common areas (e.g., basketball and tennis courts). The central common area is an area of open space which is integrated into the development and serves as an area where all residents of the community can gather for informal recreational activities. Up to five (5) percent of the area may be used for picnic areas, formal/informal gardens and similar uses. This five (5) percent may be exempted from remaining in an undisturbed state.

(e)        The size of the central common area may be reduced if it assists in protecting other significant environmental resources.

(7)        Safe and convenient pedestrian access as well as access for maintenance purposes shall be provided to the common open space. Due to environmental reasons, limited pedestrian access shall be provided through Urban Transition Buffers (UTBs) and floodplain areas.

(8)        The additional common open space shall be shown on the site and/or subdivision plan, with a notation to indicate that the common space shall not be used for future structures.

(9)        The developer shall establish and incorporate a property owners association, which shall have the responsibility for maintaining the local neighborhood open space and associated facilities at its own expense.

(10)       As an alternative to a property owners association, a private, non-profit organization, whose primary purpose is open space conservation or preservation can own and manage the common open space within a cluster housing development.

(11)       A portion or all of the additional common open space may be conveyed to the Town for use as greenways and parkland, provided it meets Town standards for such facilities and is agreed to by the Town. Such conveyance would occur at no cost to the Town.

8.4.9     Use of Open Space and Facility

The reserved common open space may be used for the following:

(A)        Open space uses that are primarily passive in nature, including wildlife sanctuaries, forest preserves, nature centers, trails, picnic areas and similar uses;

(B)        Conservation of natural features in their existing state;

(C)        Re-vegetated bio-retention areas;

(D)        Agricultural activities consistent with the open space being preserved; and

(E)        Utility lines and associated easements

(F)        Such uses shall not include rights-of-ways for roads or parking areas, tennis courts, swimming pools, or similar recreational development. The use of open space may be further limited or controlled at the time of final approval where necessary to protect adjacent properties.